To prevent search engines from indexing identical content across your sites and punishing you for “duplicate content”, you can set the canonical tag on your sub-sites to the URL of the content on your source site.

To get the URL of the entity on the source site, you can use:

// The following snippet assumes that a node entity is available as a $node variable
// that you want to get the source URL for.

$source_url = NULL;
$status = \Drupal\cms_content_sync\Entity\EntityStatus::getInfosForEntity(

foreach ($status as $candidate) {
  if ($candidate->isSourceEntity()) {
  $source_url = $candidate->getSourceUrl();
  if ($source_url) {

// The variable $source_url will now be the full URL to the content on the source site
// or NULL if the node wasn't pulled from another site- in this case you can just use the
// local URL of the node instead.

Please note that path aliases are not used for the source entity URL as they may change.